비정렬 격자계에서의 물-기체 2상 유동해석코드 수치 기법 개선

IMPROVEMENT OF A SEMI-IMPLICIT TWO-PHASE FLOW SOLVER ON UNSTRUCTURED MESHES

  • 이희동 (한국과학기술원 대학원 항공우주공학과) ;
  • 정재준 (한국원자력연구원 열수력안전연구부) ;
  • 조형규 (한국원자력연구원 열수력안전연구부) ;
  • 권오준 (한국과학기술원 항공우주공학과)
  • 발행 : 2010.05.13

초록

A thermal-hydraulic code, named CUPID, has been developed for the analysis of transient two-phase flows in nuclear reactor components. A two-fluid three-field model was used for steam-water two-phase flows. To obtain numerical solutions, the finite volume method was applied over unstructured cell-centered meshes. In steam-water two-phase flows, a phase change, i.e., evaporation of condensation, results in a great change in the flow field because of substantial density difference between liquid and vapor phases. Thus, two-phase flows are very sensitive to the local pressure that determines the phase change. This in turn puts emphasis on the accurate evaluation of local pressure gradient. This paper presents a new numerical scheme to evaluate the pressure gradient at cell centers on unstructured meshes. The results of the new scheme for a simple test function a gravity-driven cavity, and a wall boiling two-phase flow are compared with those of the previous schemes in the cupid code.

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